We upgraded to ESX 3.5 u2 Build 110268 4 or 5 weeks ago and we need to create a brand new VM. I can't boot off CD! I've checked the BIOS settings on the VM, all set fine. It makes no difference whether I try the CD drive within the ESX server, or an ISO or whether I connect it via the VI client. I've checked the VI client still passes the CD through on current VMs, and it does - so, er, does anyone have any insights please? 
I've googled far and wide but I'm not coming up with anything.
Thanks for any help.
Scott
Hi, thanks for getting back. But bad news. 
That doesn't work either. It doesn't boot off an ISO of a CD-ROM even when going into the edit settings, connected and CtrlAltins as you've suggested.
A bit more information that I should have included in my original post - on the VM when booting up to a CD that is in my PC and I've sharing it through the VI client, I get the following error message. "You do not appear to have a valid-CDROM device. If this is a CD-ROM device, try enabling legacy emulation mode." However, if I share the CD through the VI client to an active VM that is already up and running, it passes the CD through fine.
:smileygrin: Yes - got it working. I think this is the advice that Donnie Q gave me too. But here is the exact process that I did to get it working.
I tired booting off an ISO CD again. The PXE boot was still on screen. Went to edit settings, changed the CD-ROM connection to the VI client. Clicked on the toolbar so it connected, and I lazily just pressed Esc on the PXE. Importantly what I did NOT do and what I was doing on other times, was restart the VM. The CD-ROM booted!
Hope this info helps others out - I need to find out why the ISO will not boot.